Responding officers found a suicide note weighed down with a knife on the ledge where Thomas had been. The knife was not used to harm anyone, police said.

The note was addressed to the renter of the apartment, an older female friend of Thomas'. Thomas was living there with the friend, the friend's teenage son and 19-month-old Justin Stephens, her baby.

Emergency medical personnel found Stephens unconscious in the apartment and rushed him to Community Hospital. He was pronounced dead at 8:42 p.m., though Thomas said in her suicide note that the baby had been dead "since three."

The suicide note told her friend that she had been attempting suicide since the day before, and thanked the friend for giving her a place to stay.

"Justin has been dead since three and I am dead too," the note read, according to a law enforcement source. "I killed him. I'm sorry. Everyone was right."

A law enforcement source said Thomas told police that she smothered her baby to spite the baby's father because she believed he was involved with another woman.

Thomas had no prior arrests, police said, and no documented history with mental illness or with the Administration for Children's Services.